Chronic cutaneous wound complications account for an estimated $20 billion of health care costs annually in the U.S. Healing chronic wounds involves monitoring at specific intervals and changes to plan of care when needed. Monitoring the wound involves a series of measurements taken by a clinician. The collected wound data is then analyzed to determine the most effective plan of care. Patients, physicians or nurses are then able to make changes to the plan of care based on the analysis. This is an iterative process that typically takes place once or twice per week or as needed until the wound is healed. Inaccurate assessment leads to an ineffective plan of care which leads to higher health care costs, longer healing times, and in some cases loss of limbs or lives.
Through patient and subject matter expert consultation, Applicant has determined that the current wound assessment process is largely subjective, inconsistent, and inaccurate. Market research has indicated that there are currently no available processes, techniques, devices, or systems that fully meet the need for non-subjective, accurate, and consistent wound assessments. Through research, Applicant has determined that inaccurate assessment primarily stems from the subjectivity and inaccuracy of the measurement and analysis process that is currently used.
Applicant has categorized the current wound assessment process into two primary categories which include patient and wound specific data collection and data analysis.
Patient specific data collection involves collecting patient demographics, comorbidities, socioeconomic state, general nutritional state, and vital signs. Wound specific data collection involves collecting wound surface measurements, tunneling measurements, undermining measurements, tissue coloration, drainage coloration, drainage odor, and peri-wound tissue temperatures.
Data analysis involves comparing nominal measurements over time, associating tissue colorations and temperatures with various degrees of tissue health, associating drainage characteristics with various degrees of wound health, and associating patient specific information with symptoms that are present. Some of these analyses are performed at the patient bedside by the immediate care clinician during the wound assessment. Others are performed after the assessment by physicians or other wound care experts. Ultimately, it is the data analysis on which the most effective plan of care is based.
Nominal measurements of a wound typically include surface length, surface width, depth at deepest point, depth of undermining, extent of undermining, depth of tunneling, and extent of tunneling. Qualitative data that is typically noted by the wound care clinician during a wound assessment includes drainage amount, drainage color, drainage odor, tissue coloration, tissue texture, and relative tissue temperature. Qualitative data is collected visually or by touch.
The current most commonly used wound assessment procedure states that the greatest length, greatest width, and greatest depth of the wound are to be measured. The clinician uses his/her own judgment to determine the longest and widest points which are typically measured using a ruler.
Depth information is generally acquired using a cotton-tipped applicator and a ruler. The clinician again uses his/her own judgment to determine the deepest point in the wound. The cotton-tipped applicator is inserted into the deepest point of the wound and grasped such that the thumb marks the point at which the surface plane of the outer tissue intersects the applicator. The ruler is then used to measure the distance from the tip of the thumb to the tip of the applicator, indicating the depth of the wound
Location measurements are typically referenced to an imaginary clock face which is oriented such that 6 o'clock is closest to the patient's feet. The angular extent of undermining is typically noted using the clock face method. For example undermining may extend from 1 o'clock to 5 o'clock.
The depth of the undermining is also measured using a cotton-tipped applicator in the same fashion as wound depth. Tunneling location is noted with reference to the clock face.
Tunneling depth is measured using a cotton-tipped applicator and ruler in the same fashion as wound depth.
The data acquisition methods described in the previous paragraphs have proven insufficient in many ways. First, the subjectivity involved with the visual determination of the longest, widest, and deepest points of the wound tends to result in large inconsistencies in the surface measurement data. This data is typically used to determine healing progress and, as a result, healing progress is frequently misinterpreted.
The use of rulers in making surface measurements has also been problematic. The relatively low resolution of the ruler does not provide adequate insight into new tissue development over time. For example if a ruler with 1 mm resolution was used to make a depth measurement of 1.0 cm then technically at least 0.5 mm of new tissue growth must occur before the next measurement for any healing progress to be recognized.
Also, the spongy texture of tissue makes it hard to rely on measurement instruments such as rulers or cotton tipped applicators to provide accurate and consistent data. The pressure applied while holding the measurement instruments down onto the tissue would have to be consistent between measurements in order for the measurements themselves to be consistent.
The positioning of the patient also tends to vary from measurement to measurement. Positioning the patient differently can result in stretching of the wound which distorts the wound differently with each position. This makes it extremely difficult to collect accurate and consistent measurement data.
There are several other factors that contribute to the inconstancy and inaccuracy of the data collected using currently accepted techniques. These factors include positioning and referencing of the clock face to determine tunneling location and angular extent of undermining, visually acquiring and interpreting tissue coloration and texture, and visually acquiring and interpreting drainage coloration and amount.
The data collected from the wound is analyzed to classify the wound and determine the most effective plan of care. It's safe to say that inaccurate data will result in inaccurate analysis results. Even with accurate data, the analysis techniques used to classify the wound and determine the most effective plan of care have proven inconsistent between clinicians. Clinical experience and academic background of the performing clinician tend to be key factors in how accurate the analysis results are.
The classification of the wound is determined by wound thickness, wound location, wound shape, drainage, odor, tissue coloration, tissue temperature, and tissue types present. Throughout the wound assessment, the clinician uses this information to “paint a picture” in their head by associating symptoms with patient or wound specific data. The ability to do this effectively relies heavily on the clinical experience and academic background of the clinician.
The most effective plan of care is determined based on the classification of the wound. If the wound is not classified properly, the most effective plan of care may not be implemented which can result in further injury to the patient, higher health care costs, and possibly loss of limb or life.
Currently, Applicant is aware of three prior art systems on the market which perform some, but not all, of the parts of the Wound Measurement and Tracking System of the present invention. “The Scout”, sold by Woundvision, is an infrared and visible 2D imaging system. A visible camera is used to take high resolution images of the wound. The data processing software employs an edge detection algorithm to detect wound edges and determine length, width, and area measurements. A long-wave infrared imaging device allows the user to measure surface tissue temperature. This information is used to indicate areas where deep tissue injuries have occurred and where ulcers may be forming. The Scout does not provide 3D measurement capability, undermining measurement capability, or tunneling measurement capability. The Scout also does not provide tissue type analysis, wound classification analysis, or plan of care recommendation.
A device called “Silhouette”, manufactured by Aranz Medical, is a 3D measurement and wound documentation system designed to be used at the point of care. The Silhouette measures area, depth, and volume of wounds along with healing progress in the form of new tissue growth. This company offers a secure internet accessible database that stores and consolidates the information obtained from the devices so that data can be shared with other clinicians. The Silhouette does not provide tunneling, undermining, or tissue temperature capabilities. The Silhouette also does not offer tissue type analysis, wound classification analysis, or plan of care recommendation
A company called eKare incorporated has developed a 3D imaging and analysis system that acquires a color 3D image of the wound. The 3D image data is analyzed by a software application that determines maximum length, maximum depth, maximum width, wound perimeter, wound area, volume, and tissue types by percentage. The eKare system does not measure tunneling or undermining and does not classify the wound or provide a plan of care recommendation.
The Wound Measurement and Tracking System of the present invention addresses all of the deficiencies observed in prior art systems. Extensive research was done to determine exactly what the user needs are and those needs were propagated through the engineering design process. Applying the systems engineering process in the development of the WMTS has resulted in a system that ultimately meets the needs of the user as no prior art device can. Prior art devices typically only identify one key technology and search for an application. This means that they focus on finding a way to use the technology that they have and not on the needs of the users This results in user needs not being fully met as is the case with the three competitor products mentioned in the paragraphs above. For this reason, most wound care clinicians are not using any one of the competitor systems. Instead, the inaccurate, subjective, and inconsistent ruler/clock face techniques are still used by a large majority of wound care clinicians. This evidences a long felt need in the industry has still not been met.
Thus, the need in the art for a wound measurement and tracking device is clear and the objective of the present invention is to provide a structure and system that addresses these and other needs in the art as is more fully described hereafter.